1. Field of the Invention
The invention relates to a lamp lens device. Specifically, the invention relates to a lamp lens device such as a tail lamp, etc. that can transmit a communicative signal to other drivers and/or to other persons. An object of the invention is to improve the external appearance of a vehicular lamp device, both when the lamp device is lit and when the lamp device is not lit.
2. Discussion of the Related Art
FIG. 7 shows an example of the construction of a lens 90 used in a conventional vehicular lamp device. Light from a light source that is a quasi-point light source such as an incandescent light bulb, etc., strikes an inner lens (not shown in the figures) on which Fresnel cuts are formed, so that the light is transformed into parallel light rays. The parallel light rays strike a lens 90 on which lens cuts 91 have been formed to achieve appropriate diffusion and obtain desired light distribution characteristics.
Each individual element of the above-mentioned lens cut 91 is formed with a convex lens shape or concave lens shape, and a plurality of lens cuts 91 which are formed with the same curvature and same shape are formed so that the cuts cover the entire surface on the light sources side of the above-mentioned lens 90.
In the conventional lens 90, when the light source is lit, the light is focused at a focal point after passing through the lens 90 where the lens cuts 91 have a convex lens shape. Since the lens cuts 91 have the same curvature and the same shape, the position of this focal point is located on a plane at a predetermined distance in front of the surface of the lens 90 in the illumination direction of vehicle lamp 90.
When the lens 90 is viewed from outside the front side of the vehicle lamp 90 while the light source is not lit, vision is focused by the respective lens cuts 91 at a focal point located on a plane that is a predetermined distance behind the lens 90. Accordingly, when the surface of the lens 90 is viewed from the front, regardless of whether the light source is lit or not lit, the lens 90 as a whole appears to be very planar and does not appear to be of quality construction as a result of the above-mentioned planar focal point. Thus, the lens lacks a feeling of depth and appears to be quickly and cheaply constructed with no forethought to the aesthetic design and appearance of the lamp. Furthermore, similar problems occur when the above-mentioned lens cuts 91 have a concave lens shape.
The lack of a feeling of depth in the conventional lens 90 deprives the designer of the lens from constructing a lens that ties artistic lighting qualities with the functional lighting requirements in a vehicle lamp. Accordingly, the conventional vehicular lamp lens 90 does not fully contribute to an improvement in the design of the vehicle body.
Tail lamps and brake lamps, etc., are signal lamps and therefore their functional requirements are most important. However, since such lamps are components that add to the appearance of a vehicle's external body, it is also important that these lamps contribute to the. aesthetic qualities in the design of the vehicle body.